High-frequency modulation device



Sept. 11, 1923. 1,467,596

P. 1. WOLD HIGH FREQUENCY MODULATION DEVICE Filed May 28 1918 Patented Sept. 11, 1923.

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PETER IRVING WOLD, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO WESTERN ELEC- TRIO COMPANY, INCORPORATED, 015 NEW YORK, N. Y., A CORPORATION 01E NEW YORK.

men-FREQUENCY monum'rron nnvron Y Application filed May 28, 1918. Serial No. 237,120.

To all whom itmag concern Be it known that I, PETER IRVING VVOLD, a citizen of the United States, residing at East Orange, in the county of Essex, State of New Jersey, have invented certain new and useful Improvements in High-Frequency Modulation Devices, of which the following is a full, clear, concise, and exact description.

The object of this invention is to provide a means and method for producing modulated high frequency oscillations.

This invention relates to a system wherein a condenser transmitter is associated with an electronic or other potential operated device for modulating or otherwise varying oscillations in accordance with yariable wave signals. i

In one aspect the invention resides in associating a condenser having an electrode adapted to vibrate at the frequency of sound waves with a thermionic or equivalent repeatingdevice having a feed-back connection.

One object is to so associate a condenser transmitter with a high frequency nerator that the condenser may be polarlzed to a sufiiciently high degree for eflicient-action without disturbing the action of the generator.

The invention as herein exemplified, remdes in a system in which a condenser transmitter is associated with a typical form 0f\ oscillation generator of the audion or equivalent electronic 'discharge type for modulating the oscillations generated thereby in accordance with speech or other signals.

Condenser transmitters have heretofore been of slight value for practical application because, while they are quite free from distortion, the systems in which they were employed were of small efliciency from an energy standpoint. Howeyer, with the development of voltage operated modulating devices of the type herein disclosed which require practically no current but only a change of potential to secure eflective modulation, the utilization of condenser transmit ters for practical operation in modulating systems becomes possible. This invention 'has for aprimary object the provision of means for accomplishing this purpose. This highly desirable result is further assisted by the development and utilization of substantially distortionless and very eflicient amplifying devices whereby modulated oscillations of small energy may be amplified once or successively before utilization. Theuse of such amplifiers is, however, well known in the art and constitutes no part of the present invention which broadly relates to means for associating a device of the thermionic discharge type with a condenser telephone as a means for varying repeated or generated oscillations. Y

For the purpose of explaining the application and scope of the invention, reference is made to the accompanying drawings wherein one arrangement of circuits and devices for'carrying out the invention is diagrammatically shown. i

The highly evacuated tube 1 of the audion type contains anode 2, cathode 3 and impedance varying element or grid 4. A tuned circuit including variable capacity 5 and inductance 6 is connected between the anode and cathode. The frequency of oscillations generated may be conveniently varied by changing the tuning of this circuit. Con denser transmitter 7 is conventionally shown as connected between the grid 4 and cathode 3. One terminal of the condenser is conductively connected to the grid and the other to the cathode. High resistance 8 is in parallel with transmitter 7. The resistance 8 allows the condenser transmitter 7 to be polarized Capacity 14 is preferably variable and is adjusted so that high frequency variations will pass readily but considerable impedance will be oflered to low frequency variations, thereby preventing variations of potential upon the grid, caused by condenser transmitter 7, from being shortcircuited. Inductance 15 on the other hand is adjusted to allow low frequency variations to .pass readily but to prevent high frequency varia= tions which are fed back through'connection 12 from being short-circuited through trans mitter 7. Coil 16 is coupled to coil 6. Vanable potentials upon the grid of the modulating tube will cause corresponding variation of amplitude of the generated oscillations which will then be modulated in accordance with signals. Line 17 and coil 16 typify any suitable means for leading away the modu lated high frequency currents for w1re or wireless signaling or any other desired purcondition is effected which. causes an ad ditional electromotive force corresponding to the signal to be impressed upon thegrid of the modulator.

The invention is not limited to theembodiment herein described and illustrated but may be involved in other constructions. The appended claims define the novel features of the invention both broadly and specifically.

What is claimed is:

1. The combination of an oscillation generating system including an input circuit, an output circuit and a feed-back circuit, and a condenser transmitter conductively connected to the input circuit thereof'for modulating in accordance with speech the oscillations produced by said generating system. i

2. The combination of an oscillation generator including an input circuit, an'loutput circuit and a feed-back circuit, and a' condenser transmitter operatively associated with 'one of said circuits for modulating in accordance with speech the oscillations produced thereby. 3. In combination, an oscillation generating system including spaced electrodes be- A tween which a space discharge occurs and an impedance varying element for varying the impedance of said space, and a condenser transmitter for changing the potential. of said impedance varying element in accordance with speech waves. a

4. In combination, a generator adapted to.

produce continuous electrical oscillations of constant amplitude, and a condenser transmitter operatively associated with said gen erator for varying the oscillations in accordance .with speech waves.

5. A generator of oscillatory electric cursaid anode and said cathode, an input circuit between said cathode and said impedance varying element, a condenser transn1itter adapted to be operated by speech Waves included in said input circuit, and a feed-back connection from said tuned circuit to said input circuit. v

7. The combination of an electronic discharge device having an input circuit, an output circuit, and a feed-back connection with a condenser transmitter adapted to be actuated by speech waves operatively associated with one of said circuits, and a potential source for polarizing said transmitter.

8. The combination of an electronic discharge device having an' input circuit, an output circuit and a feed-back connection, a condenser transmitter adapted to be actuatediby speechwavesincluded in said input circuit, and means for polarizing said transnutter.

9. The combination of an electric discharge device with means comprising a cathode, an anode and an impedance control electrode for producing electrical oscillations and a condenser transmitter adapted to be actuated by speech waves for causing the discharge device to vary said oscillations repeated thereby inaccordance with speech waves acting upon said condenser transmitter.

10. \The combination of an electronic discharge repeater with a source of high frequency variations connected to theinput circuit thereof, a condenser transmitter adapted to be actuated by speech waves, and connecting means for causing said repeater to repeat the high .frequenc variations in a varying manner depen ent on varying conditions of said condenser.

11. The combination of an electronic discharge amplifier witha source of high frequency variations connected to the input circuit thereof, a condenser transmitter adapted to be operated by speech waves, and connecting means for causing said amplifier to variably amplify the high frequency variations in accordance with instantaneous' changes of capacity of said transmitter. 1

12. In combination,'means for. establishing an electron stream, means for maintaining a static charge in the vicinity of said stream to act thereupon, means for periodically varying said charge at high frequency, means to normally produce a static balancing of a plurality of electromo'tive forces, means for disturbing the balance in accordance with speech waves, and means for causing the unbalanced condition to maintain a slowly varying additional charge in the vicinity of said stream.

13. A high frequency generating system comprising an evacuated vessel, an anode and a cathode therefor, means for producing current between said anode and cathode, impedance controlling means for varying the current thercbetween, an input and an output circuit for said vessel, said circuits being coupled, a condenser transmitter serially arranged between said cathode and impedance controlling means. a tuned circuit for determining the frequency of the generated current substantially independently of the capacity of the condenser transmitter, and means for preventing said transmitter from 'shunting high frequency cur rent from said input circuit.

14. The method which comprises establishing an electron stream, maintaining a static charge in the vicinity of said stream to act thereupon, periodically varying said static charge at high frequency, normally producing a static balancing of electromotive forces, disturbing the balance thereof in accordance with speech waves, and causing the unbalance to maintain a slowly varying additional charge in the vicinity of said stream.

15. The method which comprises establishing an electron stream, maintaining a static chargein the vicinity of said stream to act thereupon, periodically varying said static charge at a high frequency, normally maintaining a system of balanced electromotive forces comprising static charges, periodically varyingthe spacial relation of said charges at a relatively low frequency to unbalance the system, and causing said unbalance to maintain a. correspondingly varying additional charge in the vicinity of said stream to vary the same. 16. In combination, an electron discharge device having an anode, a cathode, and an element for controlling the impedance therebetween, a source of energy for supplying current between the cathode and the anode, circuit arrangements connected to said anode, cathode, and element and forming with said electron discharge device means for generating oscillations of a given frequency whose amplitude is dependent upon the average potential of said impedance controlling element, and a condenser transmitter having a source of potential associated therewith connected to said device for varying the potential of said element with respect to said cathode in accordance with speech waves.

In witness whereof, I hereunto subscribe my name this 21st day of May, A. D. 1918.

- PETER IRVING WoLD. 

